Apparatus for reeling wet paper



Sept. 13, 1960 v I 'r G|B3QN 2,952,201

APPARATUS FOR REELING WET PAPER Filed NOV. 23, 1956 INVENTOR. THOMAS M. GIBSON ATTORNEYS United States PatentO "ice APPARATUS FOR REELING WET PAPER Thomas M. Gibson, Altadena, Calif., assignor, by mesne assignments, to Consolidated Electrodynamics Corporation, Pasadena, Calif., a corporation of California Filed Nov. 23, 1956, Ser. No. 623,947

2 Claims. (Cl. 95-94) This invention is concerned with the reeling of long strips of wet paper emerging from a liquid bath and more particularly with the treatment of strips of photographic paper undergoing development.

Oscillographs and the like produce their records on long strips of photographic paper. Such a strip is passed continuously through the oscillograph from one reel to another while one or more moving light beams controlled by galvanometers or the like produce exposed traces in the silver emulsion on the moving strip. Subsequently the strip must bedeveloped and fixed so that the traces become permanently visible. To this end processing equipment has been developed in which the paper strip isreeled continuously through a succession of liquid baths,

through or over drying equipment and then collected :again on a positively driven reel or drum. One such type of processing equipment is described and claimed ,in co-pending application Serial No. 433,701, filed June 1,

1954, by Harold L. Dsenis now United States Patent No. 2,788,587, granted April 16, 1957.

Processing equipment of the type described above operates satisfactorily at moderate speeds with strips of photographic paper that is relatively thick. Thus, little trouble is encountered in such equipment while it is processing photographic paper that is .005 inch or more in thick- .ness at linear speeds not exceeding ten feet per minute. Recently, however, much thinner photographic paper has come on the market and has caused difficulty in process- .ing equipment.

Such thin paper when wet tends to wrinkle seriously, even at speeds below ten feet per minute. Apparently the paper tends -to expand rapidly ,transverse to the direction of travel as it becomeswet and the wrinkling may be attributable to this cause.

Whatever the cause, the fact remains that longitudinal wrinkles. tend to form on the wet paper as it is drawn improvements overcome the wrinkling brought about by the use of the thin paper and also permit both thick and thin papers to be processed at speeds several times those which heretofore were maximum even for thick paper.

" Thus, with the improved apparatus of my invention photogra phic papers with a thickness of only .008" may be transported at linear speeds in-excess of fifty feet per minute without difliculty. In consequence, the capacity of processing apparatus for photographic paper been increased at least five times in the case of the thlcker paper and much more than this in the case of thin paper.

My invention contemplates apparatus. of the class described, in which a long strip of paper (particularly photographic paper) is wetted and reeled onto a rotating drum or take-up reel to which one'end' of thepaper is attached and provides a combination which comprises a tank containing a bath of liquid through which the strip Patented Sept, 13, 1 96i! is passed and in which it is wetted prior to being rolled onto the drum and an idler roller disposed above the bath and between the bath and the drum with the strip passing over and in contact with the idler roller as it moves from the bath to the drum. The surface of this roller in contact with the paper must be smooth and com posed of tetrafluorethylene resin. Preferably, a wiper member is disposed adjacent the strip and the roller and extends in the direction of the axis of rotation of the roller. This Wiper member; is pressed against the Wet strip which in turn is pressed against the surface of tetraliuoret-hylene resin on the roller. For reasons which are not completely understood the passage of the wet paper over the surface of tetra; tluorethylene resin on the roller eliminates all tendency of the paper to Wrinkle. This result may be due, at least in part, to the fact that the wet silver emulsion on the paper has only a slight tendency to come off on the surface of tetrafluorethylene and thus change the frictional coeflicient of the surface.

The presence of the surface of tetrafluorethylene resin on the roller permits the pressure of the wiper to be increased several times, thus reducing the amount of liquid entrained by the paper as it travels from each bath. This represents an important saving in the amount of chemicals required for developing and fixing the photographic images on the paper.

j grams on paper strips;

Preferably the idler roller is disposed immediately above the tank in which the bath is. contained'so that excess liquid dripping from the roller, or from the roller and the wiper, falls directly back into the path.

If desired, the roller may have a slight swell in its central portion so that it is not quite cylindrical, but tapers toward its two ends. In other words, the cross section of the roller is everywhere round but greatertoward the center. It has been found that rollers so constructed may be operated at somewhat greater speeds without danger of wrinkling.

It has also been found that some increase of paper speed can be obtained if the tetrafiuorethylene surfaced roller is provided with two sets of spiral grooves starting from the center and extending in opposite directions to- Wards the ends of the rollers. Thus one of the threads is right hand while the other is left hand. If the roller .is to spread the paper transversely as it passes overath e is turned in the right direction the effect of these grooves roller.

The'idler rollers ofthe combination may be constructed in several ways. I prefer to employ a metal roller, say

a solid cylinder or a tube of stainless steel coated wit-ha ,ethy-lene resin.

- These and other aspects of my invention will be understood more thoroughly in the light of the following detailed description This is illustrated by the accompanying drawings, in which:

c Fig. l -is a schematic longitudinal sectional view-of equipment constructed in accordance with my invention for developing, fixing and drying photographic oscillo- Fig. 2 is an enlarged view of an idler roller for the apparatus of Fig. 1 constructed of stainless steel tubing supported on nylon bearings and having its major surface slightlyswelled in the center and coated with tetrafiuorethylene resin; and i of a cylindrical relatively thick walled tube of tetrafluorethylene resin having nylon stubs in the ends and PW a 3 vided with spiral threads or grooves which tend to spread the paper transversely as it passes over the roller. i

The oscillogram processor of Fig. 1 comprises a generally rectangular. case 10 with a light-proof magazine 11 11 1 the upper portion of its forward end. A tail reel 1 2 cf exposed photographic paper 13 is disposed in this magaz ne and the paper, as it is unreeled from this magaarne, passes through a gland 14 into an intermediate l ght-proof compartment 15. This compartment contains a'series of four tanks. The first, 16, contains aqueous slsvslcpmsm li t gn he o d contains p bath which stops the action of the development solution while the third, 18, and the fourth, 19, contain stabil ation chemicals. In the bottom of each tank is a In rged idler roller 20 and, in the compartment above v there is an unsubmerged idler roller 21 Photographic paper leaving the tail reel passes over the sub- :r nerg'ed idler roller in the first tank, is carried upward and over the first unsubmerged idler roller above the first tank and thence down and up through the other baths and over the other idler rollers. As it leaves the last unsubmerged idler roller the paper passes through a gland 22 and thence over a heated drum 23. There it dried and, thereafter passed over idler rollers 23A, 23B te be finally wound on a positively driven head or takeup reel 24.

The presently preferred construction of the several unsu'hmerged idler rollers is shown in Fig. 2 wherein a tubular-"roller base 25 of stainless steel or the like is provided with nylon female bearings 26 at its ends, these heing. firmly afiixed by press fitting, to the roller base. Each nylonbearingrideson a metal stub shaft 27 which isff astened in a base 28 The outer surface of the metal roller base may be enlarged slightly toward the center, as shown. This. tends to spread the moving paper laterally and at the same time keeps it centered on the idler roller. The surface of the roller base has a thin coating of tetrafluorethylene resin. This coating is formed conveniently from an aqueous dispersion of the resin applied to the outside of the roller by spraying or dipping.

The resulting coating is dried and thereafter baked to weld the discrete. plastic particles of tetrafluorethylene in the suspension into a tough flexible continuous coating firmly bonded tothe underlying metal. 1

I prefer to employ an aqueous dispersion containing 45% to 50% tetrafiuorethylene resin by weight. Such a andits application is described in detail in an article beginning at page 1800, vol. 44 of Industrial. and Engias t ns. Chemi t (A st 2% A t e h. trip cation 'the resulting coating is dried toremove the water .and then fused at a temperature ranging from 675 Ffto 7:50" I prefer to apply two, or three coats, the final thickness of the resin on the roller being from to 4 5 of an inch. The resulting coating'is smooth and al so hs u t n al yv 0 t An alternative roller for use in the apparatus of Fig. 1 is illustrated in Fig. 3. In this case the roller is formed from a thick-walled tube 30 extruded from tetrafluorethylene resin. The tube is supported at both ends by plugs 31 of'nylon. press-fitted into the ends and carrying integrally formed stub shafts 32 that ride inconventional metal journals 33.

The cylindrical outer surface of the idler roller of Fig. 2 has two sets of spiralgroov es, each beginning near the middle of the roller. One set, 34, is right hand; the other, 35, is left hand, so that when the roller is rotated in the direction indicated by the arrow 36, the paper tends to be spread laterally as it passes over the roller. The type of idler roller illustrated in Fig. 2 is to be preferred over that of Fig. 3.in that it is stronger, cheaper and equally useful.

"Neitherthe grooves nor theswelling on the idler roller is essential, and; good results have been obtained with a 4 simple cylindrical roller coated with tetrafluorethylene resin.

In the apparatus of Fig. 1 equipped with the unsubmerged idler rollers coated with tetrafluorethylene, the photographic paper merging from each tank is wiped by a spring loaded wiper 37 which presses the paper against the unsubrnerged idler roller. This wipes off excess solution which drops into the tank immediately below the unsubmerged idler roller.

As previously indicated, the photographic paper may be reeled through the oscillogram processor of Fig. 1 at high speeds without fear of paper wrinkling or jamming. Thus, paper as thin as .003. inch may be reeled through the apparatus at linear speeds as high as 50 feet per minute, whereas previously without the tetrafluorethylene coated rollers safe speeds were substantially below 10 linear feet per minute. In the improved oscillogram processor of the invention the speed of paper travel is now limited. by. the drying capacity of the apparatus.

After long service, the rollers of Fig. 1 may tend to accumulate a slight deposit of silver-containing precipitate or emulsion. If this is allowed to remain wrinkling may result. To avoid this the unsubmerged idler rollers may be cleaned periodically with an acetic acid solution which removes the silver deposit without attack on the tetrafiuorethylene resin and restores the original condition under which wrinkling does not occur.

I claim:

1. In apparatus in which a long strip of paper coated with photographic. emulsion is wetted and reeled onto a drama, the combination which comprises a tank containing a bath of liquid, guide. means submerged in the bath over which the strip passes and is wetted prior to being reeled onto the drum, a rotatable idler roller disposed directly. over the bath and between the bath and the drum with the strip passing over and in contact with the idler roller transverse to its axis of rotation as the strip moves from the bath to the drum, the surface of the roller in contact with the paper being smooth and composed of tetrafluorethylene resin, means for pulling the paper over the idler roller, and a wiper member disposed adjacent the stripiand pressing the wet strip against the surface of st aflu r hy e oa hs ll r- 2. In apparatus in Whicha long strip of photographic pape s w ed. d tcelsi ntq a M ti drum, the bination which comprises a tank containing a bath of liquid, guide means. submerged in the bath over which the strip passes and is wetted prior to being reeled onto the drum. and an idler roller disposed directly over the bath and between the bath and the drum with the strip passing over. and in contact with the idler roller as it moves from the bath to the drum, the surface of the roller incontact with the paper being smooth, and composed of tetrafluorethylene resin, and means for pulling thepaper over the idler roller.

References Citedin the file of this patent UNITED. STATES: PATENTS OTHER REFERENCES The Rubber and Plastics Age, vol, XXXV, No. 6, Ju ne et 1 7 ..an 

